Lightning-arrester



(No Model.)

' E. THOMSON.

LIGHTNING ARRBSTER.

Patented July 7, 1885.

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UNITED STATES PATENT Unites.

ELIHU THOMSON, OF LYNN, MASSACHUSETTS.

LlGHTNlNG-ARRES TER.

SPECZFICATION forming part of Letters Patent No. $21,465:, dated July '7, 1885.

Application filed November 8, 1884. (No model.)

To all whom it may concern:

Be it known that I, ELIHU THOMSON, a citizen of the United States, and a resident of Lynn, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in LightningArresters, of which the following is a specification.

My invention relates to lightning-arresters of the general class, in which two conducting plates, surfaces, or electrodes are employed, separated from each other by a short interval across which a discharge of lightning may pass by disruption to earth. When this class of arresters is employed upon lines or circuits upon which an electric current of considerable strength is usedas, for instance, an arc-light circuit-it may happen that a short or earth circuit for such current will be established through the effects of a lightning -discharge through the arrester, which discharge forms momentarily a conducting-path for the current upon the circuit, so that the latter current may form and maintain an electric are, through which the current of the circuit escapes.

The object of my invention is to overcome this danger; and to this end it consists in the combination, with a lightning-arrester of the kind described, of any suitable means whereby an arc across its electrodes or points may be interrupted.

It is well known in the art that the effect of magnetism upon an electric arc is to repel or attract the same. If the magnetism be strong enough the arc may be displaced or interrupted. A well-known similar effect may be produced by the repulsive or disruptive action of a stream of air or other liquid made to impinge upon the arc, a familiar instance of which action is seen on the extinguishment of arc lights by wind. It is also well known that an electrio arc may be interrupted or broken by increasing the space between the electrodes or conducting-points at which it is formed.

In carrying out my invention I propose to utilize any of these well-known and equivalent means of interrupting an electric are by applying them in any suitable way to the electrodes or points of the lightning-arrester, so that if, upon the passage of a lightning discharge across the space of the arrester, an arc should be formed by the current upon the circuit,

thus short-circuiting the generator, said are will be immediately interrupted and the apparatus restored to its original condition ready for a repetition of the action, and derangement or interruption of the action of the generator and devices upon the circuit prevented.

Some of the ways in which my invention may be carried into practice are illustrated in the accompanying drawings, in which- Figure 1 is a diagram of a circuit and apparatus, illustrating conditions to which my invention is applicable. Fig. 2 is a side elevation of asimple form of my invention. Figs. 3 and 4 illustrate equivalent ways of carrying out the invention. I

Referring to Fig. 1, G indicates a dynamoelectric machine or other generator of electricity-supplying current to a circuit, C, upon which are electric-arc lights or other apparatus.

L indicates one of the plates or electrodes of a lightning-arrester, separated from its opposed electrode or plate 6 by a slight insulating space sufficient to prevent escape of the current from the generator, but small enough to allow a lightning-discharge falling upon the line 0 to escape by disruptive action across the space between the plates or electrodes L c. The plate or electrode L is connected to the circuit C, as usual, and the plate or electrode 6 to the earth,in any usual or proper manner. A similar lightning-arrester is indicated at L 6 connected to the circuit on the other side of the generator. The passage of a lightningstroke across the space between such elec trodes L e L 6 forms a momentary conducting-path over which the current from the generator may flow on short circuit, an are being thus established and, once established, maintained by the current of the generator. The latter is thus virtually short-circuited, current is withdrawn from the apparatus on the circuit 0, and the generator G is also liable to injury. Other arrangements of circuit and apparatus and other conditions may obviously exist in which the evils just mentioned may occur from the discharge of a lightning-stroke across the electrodes of a lightning-arrester.

In Fig. 2 I have shown a way in which magnetism may be applied in accordance with my invention.

\V WV indicate the north and south poles of a magnet, (permanent or electro,) which our brace the plates L e of a lightniiig arrester in such way that the magnetism will tend to force any electric are between the plates upward. The plates L and e are connected one to the line C and the other to earth, and I prefer to make them in the shape shown-that is, with the space between them widening upward-so that by the action of the magnetism the are forming at the narrower space may be forced upward to the wider space and ruptured, thus causing the restoration of the current to the line C, and the continuance of the action of the lamps upon the circuit 0, if the latter still be intact. The apparatus is then ready for any possible repetition of the action. If the line has been open-circuited by the lightning-discharge, the only effect of the arrester is to open-circuit the generator G. The poles WV W may be the poles of an electromagnet, M, whose coils may be in a circuit from any desired source-as, for instance, in the normal circuit wit-h Gso as to tend to maintain a constant magnetism in the poles V; or, the coils of M may be in the circuit formed across the space between the electrodes L e. This may be effected by simply placing the coils of the electro-magnet in the connection from c to the earth E, as indicated.- In this case the current that forms the electric arc across the electrodes will serve to produce the magnetism at V WV if the cores of the magnets be of soft iron, or to increase the magnet ism if the poles \V \V be permanently magnetized. The current is thus made to serve as the agent for bringing into action the means whereby disruption is effected at L c. This particular feature of my invention may be also utilized in connection with other means for disrupting the arcas, for instance, in the way illustrated in Fig. 3, where the coils on the circuit with the electrodes are the coils of a magnet, which acts to open a valve and permit a blast or current of air to blow away the are that may form across the electrodes L e,- or in the way illustrated in Fig. 4', where the current through the electrodes and coils energizes a magnet, which gives motion to a support, upon which one of the electrodes is mounted, thus separating the electrodes sufficiently to disrupt the are.

In Fig. 3 I have shown a way of applying the disruptive effect of a blast of air or other fluid to the electrodes of the lightning-arrester. The electrodes L and e are of the usual or any desired form, and one, L, is connected to the circuit C, while the other is connected to earth. At J is indicated a jet nozzle or pipe of any proper form, directed upon the space between the electrodes L c of the lightning-arrester, and connected by a pipe, 1?, with a supply of air or other fluid or liquid under pressure. The blast or current delivered from J may be constant, or it may be controlled through the agency of the current which forms the are across the electrodes. To effect this it is only necessary, as indicated, to place the coils of an electro-magnet, M, in the circuit and to con nect the armature n thereof with a valve, V, on the pipe P. A retracting-spring or other agent keeps the valve closed normally; but the current in M opens the valve against the influence of the retractor, and the air, imping ing on the are, disrupts the latter and re-establishes the insulation between the electrodes of the lightning-arrester. In Fig. 4. the arrangement is such that the are is disrupted by separating the electrodes of the lightning-arrester. One of the electrodes, as e, is mounted on a movable lever or other support controlled by the action of the current passing across the electrodes.

D indicates a lever, which is the armaturelever of the electro-magnet M, and which is normally held against a stop, (I, by the influence of a retracting-spring, z. The elec trode e of the lightning-arrester is mounted on the lever and is normally within proper distance of the opposite electrode, L, to permit a lightning-discharge across the interval. The coils of the electro-magnet M are in the circuit, so that any current forming an arc across the space between L and 0 will energize the electro-magnet, thus causing the electrode 0 to be drawn away from the opposite electrode into the position indicated in dotted lines. The effect of this is to disrupt or break the are by separating the electrodes to such distanee that the current cannot pass. The electro-magnet thereupon loses its power, and the retractor restores the electrode 0 to its normal position ready for a repetition of the action.

In this, as in preceding instances, the current in the coils of M brings into operation (directly or indirectly) the means whereby the arc is interrupted.

It is obvious that my invention may be applied to other forms of lightning-arrester besides that shown.

lVhat I claim as my invention is 1. The combination, with the plates or electrodes in a lightning-arrestcr, of an arc-rupturing device applied thereto in the manner described, so as to rupture any are that may form across the space between the plates or electrodes.

2. The combination, with an electric circuit fed by a dynamo-electric machine or other source of current capable of forming and maintaining an electric arc, of lightningarresters connected to said circuit and arerupturing devices applied to the lightning-arresters, as described, whereby short-circuiting of the dynamo or other source after the passage of a lightning stroke may be prevented.

3. The combination, with a lightning-arrester, of an electro-magnet coil in the circuit of the discharge through the same and means for disrupting or severing any electric are that may form across the electrodes of the lightning-arrester, said means being brought into action by the current flowing through the arrester and the coils.

ICC

4. The combination, with a lightning-arresterformed by separated electrodes or plates, of an electro-magnet in the circuit with said electrodes, as and for the purpose described.

5. The combination, with a lightning-arrester, of a magnet Whose poles are arranged to embrace the electrodes or plates of the arrester, as and for the purpose described.

6. The combination, with a lightning-arrester having conducting electrodes or plates separated by an interval of irregular Width,

of means, substantially such as described, for driving or forcing an electric are from a narrow to a Wider portion of the space between 15 the electrodes.

Signed at Lynn, in the county of Essex and State of Massachusetts, this 5th day of November, A. D. 1884.

ELIHU THOMSON.

Witnesses:

THos. TOOMEY, XV. O. WAKEFIELD. 

